The field of the disclosure relates to soil treatments, and more particularly to the injection of soil treatments below the surface of the soil adjacent to obstructions, in a manner which does not mechanically disturb the soil surface.
The insertion of soil treatments below the surface of the soil has been practiced as a way of limiting the wash off of the treatments. Typical devices for implementing such soil treatments utilized needles or other mechanical devices to create a passageway into the soil to allow the soil treatment to be inserted into the ground. These devices have the obvious limitation that they create holes in the soil, which may be unsightly, or create other adverse concerns, such as unwanted soil compaction adjacent the insertion sights, as well as require the creation of the hole using mechanical forces.
The use of high pressure as a method of effectively injecting materials below the soil surface has been described in U.S. Pat. No. 5,370,069 to Monroe, titled Apparatus and Method for Aerating and/or Introducing Particulate Matter into a Ground Surface. These methods use high pressure jets of a fluid, such as air or water that entrain the soil treatment agent. The soil treatment agent may be in solution with the fluid, or may be a granular material carried with the fluid. The high pressure jet can form a small hole in the surface into which the material is being placed, or cause the material to be absorbed by the surface in a rapid fashion, such that soil disturbance is minimal. One benefit of the use of a pressure jet is that no mechanical effort is required to create a passageway as a predicate for the soil treatment material to be placed below the surface of the soil.
While devices such as that disclosed in Monroe are effective at placing soil treatment materials below the surface, they are tailored to distribution of such materials over a large area, where the size of the equipment is not a limitation. For example, the device, described in U.S. Pat. No. 7,581,684, includes a towed device which can be used to provide accurate distribution of soil treatment material over a broad area. This device is limited, however, in placing soil treatments next to structures, such as walls, fences, and/or trees or other landscape features, due to challenges associated with maneuvering the device close to the structure.
Through the use of a high pressure and/or velocity stream of soil treatment material, the material can be injected without disruption of the surface being treated. One aspect which improves this performance is the close proximity of the injector to the surface itself, such that the flow of soil treatment material does not disperse into the air when the injector is spaced apart from the surface. Additionally, contact between the injector and the soil being treated limits the ability of the soil treatment to bounce off of the soil to which the treatment is being applied.
As a result of the high pressure utilized, it is desired to address safety concerns for an operator of the device. Although the energy of a short duration flow of soil treatment material will dissipate as it travels through air, the flow can be harmful to objects located near the discharge orifices. Furthermore, such dissipation of the energy will limit soil penetration for a given pressure. Accordingly, actuation of a high pressure flow of soil treatment material only when the discharge orifices are close to the soil increases the effectiveness of the delivery device.